epilepsy
(ep'ĭ-lep‵sē 
)
[L. epilepsia fr. Gr. epilēpsia, (epileptic) seizure]
A disease marked by recurrent seizures, i.e., by repeated abnormal electrical discharges within the brain. Epilepsy is found in about 2% or 3% of the population. Its incidence is highest in children under 10 and in older adults (over 70); adolescents and adults are affected less frequently.
The International League Against Epilepsy categorizes epilepsy as partial, generalized, drug-resistant, or unclassified. Partial seizures typically begin with focal or local discharges in one part of the brain (and body); sometimes they may become generalized. When a patient remains awake during a seizure, the seizure is said to be simple and partial. If loss of consciousness occurs after a focal seizure, the seizure is said to be partial and complex. Drug-resistant epilepsy is a failure to control seizures despite adequate trials of two appropriately chosen and administered antiepileptic drugs.
Patients who suffer recurrent episodes of alcohol withdrawal or frequent severe hypoglycemia, hypercalcemia, or similar metabolic illnesses may have repetitive seizures but are not considered to have epilepsy if the seizures stop after their underlying illnesses are treated.
Causes: Epilepsy may result from congenital or acquired brain disease. Infants born with lipid storage diseases, tuberous sclerosis, or cortical dysplasia may have recurrent seizures, as may children born with intracranial hemorrhage or anoxic brain injury. Adults may develop epilepsy as a result of strokes, tumors, abscesses, brain trauma, encephalitis, meningitis, or uremia. In many instances the underlying cause is undetermined.
Symptoms and Signs: Symptoms may vary from almost imperceptible alteration in consciousness, as in absence seizures, to dramatic loss of consciousness, tonic-clonic convulsions of all extremities, urinary and fecal incontinence, and amnesia for the event. Some attacks are preceded by an aura, whereas others provide no warning. Other forms are limited to muscular contractions of a localized area or only one side of the body.
SEE: postictal confusion.
Diagnosis: The diagnosis of epilepsy is made by a careful assessment of the patient's history, augmented by diagnostic studies. Typically, these include blood tests to assess for metabolic disarray, brain imaging by magnetic resonance imaging (MRI) or computed tomography (CT), and electroencephalography. The differential diagnosis of epilepsy includes many other illnesses marked by episodes of loss of consciousness, including pseudoseizures, syncope, transient ischemic attacks, orthostatic hypotension, and narcolepsy.
Treatment: Therapy is available for the prevention and control of recurrent seizures. Antiepileptic agents include phenytoin or carbamazepine for partial seizures, valproic acid for absence seizures, and any of these agents or phenobarbital, with or without newer drugs, e.g., gabapentin or lamotrigine, for generalized seizures. All these agents may have significant side effects, and many of them have a range of drug-drug interactions.
Surgical therapy to remove an epileptic focus within the brain is used occasionally to manage seizures that have been difficult to control medically. In specialized neurosurgical centers, this may cure or reduce the impact of epilepsy in about 75% of patients.
Impact on Health: Most people with epilepsy do well with stand ard medical management, but epilepsy increases the risk of death by a factor of 2 or 3 compared to people without recurrent seizures. SYN: seizure disorder.
auditory e.Epilepsy triggered by certain sounds.
benign partial e. of childhood Benign roland ic epilepsy.
benign roland ic e.Epilepsy usually perceived as facial or oral movements or paresthesias, typically affecting children at night. The seizures sometimes generalize (cause tonic/clonic convulsions). Affected children usually outgrow the disease by the end of adolescence. SYN: benign partial epilepsy of childhood..
catamenial e.Menstrual epilepsy.
familial myoclonic e.Lafora disease.
intractable e.Epilepsy that cannot be controlled by two or more anticonvulsant drugs. SYN: medically intractable epilepsy.
juvenile myoclonic e.A form of epilepsy typically noticed in teenagers, characterized by early morning jerking movements of the extremities, and , during stress or sleep deprivation, by generalized tonic/clonic or absence seizures. SYN: Janz syndrome..
SEE: Lennox-Gastaut syndrome.
medically intractable e.Intractable epilepsy.
menstrual e.Epilepsy that occurs preferentially during particular portions of the menstrual cycle, e.g., during ovulation or menses. SYN: catamenial epilepsy.
ABBR: MTLE.
Epilepsy that begins in a focus located in the medial portion of the temporal lobe, usually in scarred tissue in or around the hippocampus.musicogenic e.Epilepsy in which the convulsive attacks are induced by music.
photogenic e.Epilepsy that occurs as a result of intermittent light stimulus.
psychomotor e.Temporal lobe epilepsy.
reading e.Myoclonic jerking, primarily of the jaw, that occurs while reading silently.
reflex e.Recurrent epileptic seizures that occur in reaction to a specific stimulus, e.g., photic stimulation while looking at flashing lights or television, auditory stimulation while listening to specific musical compositions, tactile stimulation, or reading.
refractory e.Epilepsy that cannot be controlled with two anticonvulsant drugs. Refractory epilepsy is found in about a third of all patients who have seizures.
sensory e.Disturbances of sensation without convulsions.
severe myoclonic e. of infancy Dravet syndrome.
sleep e.A term formerly and improperly used for narcolepsy.
temporal lobe e.Epilepsy originating in a temporal lobe of the brain.
SEE: psychomotor epilepsy.
Temporal lobe seizures produce one of two typical findings: (1) complex partial seizures (loss of consciousness with abnormal gesturing or automatic movements); and (2) simple partial seizures (preserved consciousness with the sense of unusual smell, taste, thought, or altered body function).
Surgery to remove the irritable focus in the brain appears more effective than treatment with anticonvulsant drugs.
traumatic e.Epilepsy caused by trauma to the brain.